The invention relates to a hub and a wheel, in particular for bicycles, and a bicycle equipped with these. The invention may be used for both front wheels and rear wheels where as a rule one or more sprockets may be disposed.
In the field of amateurs and in particular in professional cycling, the stress tolerance, weight and ease of maintenance of components are a decisive factor since the users value high-quality, lightweight, and easily maintained components. Users furthermore desire that in the case that one part of a component is defective, it should not be necessary to replace an entire component, but that in the scope of regular maintenance or if a defect occurs, particular parts can be replaced separately.
As a rule a bicycle hub consists of a hub body rotatably mounted around a hub axle comprising a hub sleeve and two hub flanges integrally formed thereon, which are provided with holes to receive the spokes which connect the hub with the rim. In the interior of the hub sleeve, at least two bearings are provided to rotatably support the hub body relative to the hub axle. The exterior bearing bushing is most often formed in the hub sleeve while the inner bearing ring or interior bearing bushing is formed on the hub axle. It is also conceivable that a separate outer bearing ring is in connection with the hub sleeve while a separate inner bearing ring is in connection with the hub axle. In such a known hub the hub flanges are strained through the spoke tension forces acting on the hub flanges and directed radially outwardly. The strain, which is dependent on the load, concurrently influences the bearing play such that changes in the spoke tension cause the operating conditions of the bearing to change. This interrelationship may lead to a reduced operating strength of the hub.
It is another drawback of this known hub that in the case that the hub flange breaks e.g. due to overload, the entire hub must be replaced. One possibility of solving this problem is offered by a hub consisting of multiple parts.
DE 94 03 506 U1 discloses a multipart hub for a bicycle where the spoke-carrying flanges are placed in a center piece and a particular link geometry is used, in particular a polygon profile. In the interior of the spoke-carrying flanges the bearings to support the hub body relative to the hub axle are provided. In this hub the radial load on the spokes also causes a strain on the hub flanges and thus a strain on the bearing seats which may adversely affect the durability of the bearings.
U.S. Pat. No. 5,829,844 discloses a hub for a bicycle where separate hub flanges are provided at the hub body to receive the spokes. The hub flanges are placed on the hub body over the hub axle ends with a kind of inner toothing at the hub flanges interacting with a kind of outer toothing at the hub body to achieve that the hub flanges are non-rotatably accommodated at the hub body. Washers and separate screws are then used to secure the hub flanges by way of the laterally applied pressure.
The drawback of this hub known in the prior art is that the washers and the large screws for fastening the hub flanges to the hub body provide additional weight. Furthermore, manufacturing the hub requires extensive work due to the required outer profile at the hub body.
EP 0 853 007 B1 discloses a flanged bicycle hub where the hub flanges for receiving the spokes are not formed integrally with the hub sleeve but are provided as separate parts. In this hub the hub flanges are pushed onto provided portions of the hub body for mounting until the hub flanges snugly fit at corresponding steps on the hub body. By screwing on fastening caps the hub flanges are axially clamped, thus being secured against slipping off.
This hub known from the prior art allows to remove the fastening caps by unscrewing and thus to replace the hub flanges of the hub so as to allow replacement of e.g. defective hub flanges. In this hub the bearings between the hub body and the hub axle are not under load from the radial spoke tension since the hub flanges are provided separately.
It is a drawback of this hub though that for one, the hub body requires a considerable radial thickness to allow the axial hub flange stops to be formed thereat. It is another drawback that large, axially screwed-on fastening caps are required for securing the hub flanges, which increases the error susceptibility and also the total weight of the hub. It is another drawback that toothings are provided on the inner periphery of the hub flange and on the outer periphery of the hub body which require extensive manufacturing steps, thus increasing the price.
In view of the indicated prior art it is the object of the present invention to provide a hub and a wheel in particular for bicycles wherein a modular structure allows replacement of individual parts. Another aspect of the object is to provide a lightweight hub.